The present invention relates to a system for the automatic detection of load cycles of a machine for the transferring of loads, wherein the machine includes a lifting apparatus for the raising of the load and a transport apparatus for the horizontal movement of the load. The transport apparatus can in this respect in particular be the slewing gear and/or the luffing mechanism of a crane.
The system in this respect includes a load change detection for the automatic detection of a load change at least on the basis of the output signals of a lifting force measurement apparatus, a load position detection which detects the position of the load in at least a horizontal direction and a load cycle detection for the automatic detection of a load cycle, wherein the load cycle detection takes place at least on the basis of the output signals of the load change detection and of the load position detection.
Systems are known in this respect from the prior art for the detection of the load cycles of transfer cranes in which the start and the end of a cycle is detected on the exceeding or the falling below of a fixed load threshold via a tared weight of the load suspension means. The crane operator furthermore has to input a trigger threshold, with the load mass being detected and being defined as a load weight of the load cycle when said trigger threshold is crossed. A slew angle of the crane is in this respect used as the trigger threshold.
The known systems in this respect have a plurality of problems which are in particular founded in the necessity of a manual interaction by the crane operator. The trigger threshold or the slew angle is thus often not set or is set at an incorrect position so that no recording or a falsified recording takes place. In addition, very high load thresholds are used for the determination of the start point and of the stop point of the cycle to avoid an incorrect detection of load cycles. Since the weight of the payload is, however, often frequently lower than the weight of the load suspension means and of the sling gear and is lower by an order of magnitude than the maximum load, a reliable detection of load cycles can thus not be ensured. In addition, the measurement system has to be configured very exactly.
Further problems result from the manual taring of the weight of the load suspension means and of the sling gear which in particular represents a frequent error source on the exchange of the load suspension means.